Hydrocodone is chemically 4,5-epoxy-3-methoxy-17-methylmorphinan-6-one. The synthesis of hydrocodone and its pharmaceutically acceptable acid addition salts are described in U.S. Pat. No. 2,71 5,629 issued to Pfister et al, and in the Merck Index, 11th Edition, page 757, entry 4708 (1989). Hydrocodone is a narcotic antitussive and analgesic. The mechanism of physiological and pharmacological actions of hydrocodone is believed that it acts directly by depressing the cough centers for its antitussive therapy. At antitussive doses, hydrocodone exerts also analgesic effects. Hydrocodone exhibits a complex pattern of metabolism including 0-demethylation, N-dimethylation and 6-keto reduction to the corresponding 6-.beta.-hydroxy metabolites.
The prior art administers hydrocodone in conventional tablet and syrup forms, which forms dose-dump hydrocodone thereby providing a concentration of hydrocodone followed by an absence of hydrocodone. This pharmaceodynamic variability with its fluctuation in hydrocodone availability to hydrocodone receptor sites produces uncertainty as it is unknown if a dose of hydrocodone is present for needed therapy. The prior art is deficient in providing controlled hydrocodone therapy to a patient seeking such therapy. The pharmacological properties of hydrocodone are known in The Pharmacological Basis of Therapy, by Gilman and Rall, 8th Edition, pg. 497, (1990); and in Pharmaceutical Sciences, Remington, 17th Ed., pg. 1104, (1985).